The remains of Ferdinand Marcos are one step closer to internment at the Philippines' Heroes' Cemetery after the defence secretary issued an order on Sunday implementing a controversial move promised by the country's new president during his campaign.

Defence Secretary Delfin Lorenzana said the directive to the armed forces is in line with a "campaign promise" by President Rodrigo Duterte to have Marcos interred at the Libingan ng mga Bayani (Heroes' Cemetery).

The order calls for the armed forces to begin preparations for the transfer.

"Kindly undertake the necessary planning and preparations to facilitate the coordination of all agencies concerned, especially the provisions for ceremonial and security requirements," Lorenzana said in a directive to the military chief.

Marcos was ousted by a five-day people power revolt in 1986 and forced to flee into exile in Hawaii, where he died in 1989.

His body was returned to the Philippines in 1993 and has since been kept in a refrigerated crypt in a mausoleum in his home town of Batac town in Ilocos Norte province, 470 kilometres north of Manila.

Past presidents have refused to have his body buried at Libingan ng mga Bayani due to allegations of corruption, human rights violations and other abuses during his 20-year rule.

But during the presidential campaign, Duterte, who took office on June 30, said he would allow the burial to finally settle an issue that has divided the Philippines for years.

He also ordered General Ricardo Visaya to closely coordinate with the Marcos family and to submit the final plan to him.

No date has been set for the burial, but local reports quoted former Senator Ferdinand Marcos Junior as saying it would take place on September 18.